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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

38922 results found.

  1. EP241107a: SVOM/C-GFT optical observations
  2. GRB 241025A: LBT optical observations
  3. GRB241105A: Gemini-South Optical Afterglow Detection
  4. GRB 241105A: VLT/FORS2 optical afterglow rapid fading
  5. GRB 241105A: Swift/UVOT Detection
  6. EP241101a: CrAO ZTSH optical observations
  7. GRB 241105A: Swift/BAT-GUANO refined analysis of short burst with extended emission
  8. GRB 241030A: optical afterglow detection from the INAF Asiago Observatory
  9. GRB 241105A: BOOTES-7 optical detection
  10. GRB 241030A: Mondy optical observations
  11. GRB 241105A: Fermi GBM Observation of a Short Burst with Extended Emission
  12. Konus-Wind detection of GRB 241105A (short with extended emission)
  13. Konus-Wind detection of GRB 241021A
  14. GRB 241105A: SVOM/VT optical afterglow observations
  15. GRB 241105A: Swift-XRT afterglow detection
  16. GRB 241105A: VLT/FORS2 spectroscopic redshift z = 2.681
  17. GRB 241104A: Swift-XRT observations
  18. GRB 240511A: LCO upper limits
  19. GRB 241104A: Fermi GBM Observation
  20. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  21. GRB 241105A: Swift ToO observations
  22. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  23. GRB 241104A: Swift ToO observations
  24. GRB 241104A: NOT optical non-detection
  25. GRB 241105A: GOTO tentative optical counterpart candidate
  26. Fermi GRB 241105A: Global MASTER-Net observations report
  27. GRB 241104A: SVOM/VT optical candidate
  28. GRB 241105A: Fermi GBM Final Real-time Localization
  29. GRB 241104A/EP241104a: Optical upper limits with Kinder observations
  30. GRB 241104A: COLIBRÍ Upper Limits on the Optical Counterpart
  31. GRB 241104A: SVOM/GRM observation
  32. EP241104a: EP detection of GRB 241104A X-ray emission
  33. GRB 241010A: host galaxy redshift z = 0.977
  34. GRB 241104A : Detection and localization by SVOM/ECLAIRs
  35. GRB 240821A: further radio observations with the VLA
  36. Fermi GRB 241104A: Global MASTER-Net observations report
  37. GRB 241104A: Fermi GBM Final Real-time Localization
  38. GRB 241030A: GRBAlpha detection
  39. EP241103a: GIT optical upper limit
  40. Fermi trigger No 752365806: Global MASTER-Net observations report
  41. EP241101a: Optical upper limits with Kinder observations
  42. EP241101a: OHP/T193 optical observations
  43. EP241103a: EP observation update
  44. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  45. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  46. EP241103a: GSP optical upper limit
  47. EP241103A: LCO optical observations
  48. EP241103a: Global MASTER-Net observations report
  49. GRB 241030A: Rapid release of TESS data.
  50. EP241101a: Global MASTER-Net observations report
  51. GRB 241029A: GRBAlpha detection
  52. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  53. Swift GRB 241101A: Global MASTER-Net observations report
  54. GRB 241101A: FRAM-ORM optical limit
  55. GRB 241030A/EP241030a: TNOT observations of the optical counterpart
  56. EP241021a: Upper limit from Konus-Wind observations
  57. GRB 241101A: Swift-BAT refined analysis
  58. GRB 241030A: further SAO RAS optical observations
  59. GRB 241030A: Optical Observations via Virtual Telescope Project
  60. GRB 241030B: Swift-XRT refined Analysis
  61. GRB 241026A: SAO RAS optical observations
  62. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  63. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  64. GRB 241101A: Swift detection of a burst
  65. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits (duplicate submission of 38023)
  66. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  67. GRB 241030A: Palomar 1-m telescope COSMOS optical observations
  68. GRB 241030B: Montarrenti Observatory optical upper limit
  69. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  70. Fermi trigger No 752083996: Global MASTER-Net observations report
  71. GRB 241030A: SAO RAS optical observations
  72. GRB 241030A: Fermi GBM Observation
  73. GRB 241030B : GIT optical upper limits
  74. GRB 241030B: LCOGT Optical Upper Limits
  75. GRB 241030B: Swift-BAT refined analysis
  76. GRB 241030A: Swift-BAT refined analysis
  77. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  78. GRB 241030B: Swift/UVOT Detection
  79. EP EP241030a: Global MASTER-Net observations report
  80. GRB 241029A: LCO optical detection
  81. Fermi trigger No 752006065: Global MASTER-Net observations report
  82. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  83. Swift GRB241030.77: Global MASTER-Net observations report
  84. GRB 241030B: SVOM/GRM observation
  85. GRB 241030B : MITSuME Akeno optical upper limits
  86. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  87. GRB 241030B: SVOM/VT optical afterglow observations
  88. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  89. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  90. GRB241030B: Fermi GBM Observation
  91. GRB 241030B: BTA observations
  92. GRB 241029A: SVOM/VT optical afterglow observations
  93. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  94. GRB 241030B: Enhanced Swift-XRT position
  95. GRB 241030B: optical observations from the INAF Asiago Observatory
  96. GRB241030B: GRANDMA/TAROT Upper Limit
  97. GRB 241030A: Swift-XRT refined Analysis
  98. GRB 241030B: SAO RAS optical observations
  99. GRB 241030B: AKO Optical Afterglow Detection
  100. GRB 241030B: Nanshan/HMT optical afterglow detection

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